We show here that global (whole body) Bmal1 -/- mice, derived from the embryonic stem (ES) cells of C57BL/6J mice, exhibited a metabolic syndrome-like onset, i.e., elevation of the level of circulating fatty acids, including TG, free fatty acids, and low-density lipoprotein (LDL)-cholesterol. This evidence concerns the gene BMAL1 and metabolic syndrome.